The invention relates to a method and an apparatus for making a joint between ends of webs made of weldable material, intended for the formation of bags for containing bulk material in general, and in particular (but not exclusively) food products in grains or small pieces or in the form of powder. The webs in such cases are expediently to be welded by means of corresponding surfaces, that is to say the two surfaces intended generally to be internal or the two surfaces intended to be external in the finished bag. In the two bobbins--that being exhausted and the new one--such surfaces are oriented in the same direction.